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Canadian Herpetological Society Société d'Herpétologie du Canada |
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Western Red-backed Salamander
Plethodon vehiculum
Family: Plethodontidae
COSEWIC status:- Not at Risk
- No Status
- Least Concern
Description
Western Red-backed Salamanders have a slender body and can reach 11.5 cm in total length. Individuals have 14 to 18 (usually 15 or 16) costal groves on each side of the body. This salamander has a black or dark grey body with a smooth-edged stripe down the back that varies in colour from yellow to red, olive or tan, although the red colouration tends to be most common. Some individuals are melanistic (all black), and this colour phase tends to be most common in coastal populations. The sides are grey to black, and the belly is grey with white flecking.
Similar Species
The Western Red-backed Salamander can be confused with the Coeur d’Alène Salamander or the Long-toed Salamander. The Coeur d’Alène Salamander has an uneven-edged stripe, 14 costal groves, large parotid glands, a heavier body and larger limbs. Also, the Coeur d’Alène Salamander only occurs in the western portion of BC and its range does not overlap with that of the Western Red-backed Salamander. The Long-toed Salamander has an irregular-edged stripe that is often green, yellow or orange (not red), a heavier body, and long toes on the hind feet.
Distribution
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In Canada, the Western Red-backed Salamander occurs on Vancouver Island and the southwestern part of the mainlined. In the United States, this species occurs along the west coast south to southwestern California.
Habitat
The Western Red-backed Salamander primarily inhabits mature and old growth forests, although they occur in younger forests as well. This species requires moist environments and is most common in areas with abundant woody debris and leaf litter. Individuals are typically absent in open habitats. This species is fully terrestrial and the eggs are deposited under logs, in rotting stumps or in other moist environments on the forest floor. Individuals overwinter below the frost line in talus slopes, mammal burrows, root hollows or other underground cavities.
Biology
Plethodontid salamanders, including the Western Red-backed Salamander, are also known as lungless salamanders because they do not have lungs; instead, they absorb oxygen directly through their skin. They must remain moist at all times so that oxygen and carbon dioxide can diffuse through the skin. Western Red-backed Salamanders breed in the fall and females lay 6–20 eggs in the late spring or early summer. The female guards the eggs until they hatch after six to eight weeks, usually in late August or September. There is no larval stage; the gills are absorbed around the time of hatching and the hatchlings are a miniature version of the terrestrial adults. Individuals reach sexual maturity in two to three years and females only breed every two years in Canada. The longevity of this species is unknown. Western Red-backed Salamanders are most active during wet weather and forage on the forest floor for insects, spiders, worms and other terrestrial invertebrates. Individuals communicate with each other though body posture and scent marking. When threatened, individuals may autotomize (drop) their tail, which creates a diversion while the salamander escapes. Although the tail will grow back over time, the individual will have lost much of the fat reserves on which it relies to survive the winter.
Threats
The primary threat to this species is the loss of mature forest, primarily as a result of logging. Pollution, such as herbicides, agricultural effluent and road salt can be detrimental to salamanders since toxins are easily absorbed though their skin. Climate change and introduced pathogens pose potentially serious future threats to Canadian salamanders.